The absence of nails can belong to one kind of nail disease, that is, the absence of nails, which can be divided into congenital absence of nails and acquired absence of nails, and acquired absence of nails can be related to lichen planus or dystrophic dystrophic epidermolysis bullosa and other diseases. 1. Congenital absence of nails: it is a nail disease caused by genetic developmental defects, often seen in congenital malformation caused by congenital hypoplasia of the ectodermal lobe, which can be related to gene mutation, and lacks one or several nails at birth. 2. Acquired naillessness: it is caused by trauma and inflammation to the nail matrix, which can be caused by such as lichen planus and dystrophic epidermolysis bullosa. (1) lichen planus: the occurrence of heredity, immunity, viral infection or psychoneurological factors, etc., for idiopathic inflammatory skin disease, the skin can have polygonal purple-red flat papules, when caused by the nail involvement can be caused by the thinning of the nail plate, can be due to progressive atrophy caused by the loss of nails, resulting in the absence of nails. (2) Dystrophic herpetic epidermolysis bullosa: it can be related to genetic factors, and when the disease involves the nails and causes atrophy and deformation of the nail plate, it can lead to the symptoms of naillessness. When you find no nails, we recommend that you go to the hospital specialist in time, the doctor will clarify the cause of the disease, and then follow the doctor’s instructions for treatment.